Health lies in healthy circadian habits | Satchin Panda | TEDxBeaconStreet


Translator: Rhonda Jacobs
Reviewer: Peter van de Ven So pathogens like this
used to cause infectious diseases that killed humans for centuries. Until sanitation, vaccination
and antibiotics took care of pathogens and gave us long, healthy lives. But now, we spend nearly half of our life fighting with these kinds
of chronic diseases, and for which there is no cure in sight. So today, I’ll share with you
some really revolutionary ideas of how to prevent, manage
and cure these diseases. And the idea is based
on the concepts of circadian rhythm, our near-24-hour rhythms. To adapt to the 24-hour light-dark cycle,
or day-night cycle, on our planet, almost every plant and animal
has circadian rhythms that are controlled by
what we call circadian clocks. These are actually encoded in our DNA. And this is so fundamental
to life forms on our planet that if we move any animal or human
from this planet to another planet that has identical conditions
as the planet Earth but has a day-night cycle
other than 24 hours, then we cannot easily survive. In recognition
of this fundamental property of circadian clocks and health, this year’s Nobel Prize
was actually awarded to three scientific leaders in this field. And I’m really honored
that all three of them have directly inspired
and influenced my research. So how do we know
that these clocks are in-built? For example, if you lock me
inside an apartment with no clue about outside time, then my circadian clock
will make me go to sleep around 10:00 at night. I’ll go into deep sleep around 2:00, and anticipating waking up, my body will warm up
around 4:00 in the morning. As soon as I wake up and open my eyes,
my sleep hormone melatonin will plummet, and my stress hormone
cortisol level will rise. My peak performance time for brain
will be around noon. And my peak athletic performance
will happen around late afternoon. As evening rolls in, the circadian clock
will crank up melatonin to make me go to sleep again, and my body will cool down
to support my sleep. So this will continue every 24 hours,
even if I’m locked inside an apartment. And these rhythms happen because
almost every single gene in our genome turns on and off
at different times of the day. Every single hormone and brain chemical also rises and falls
at different times of the day. So to have these rhythms
is actually to have health. And when these rhythms break down, when we stay awake late into the night
finishing an assignment or taking care of a loved one,
then we feel horrible the next day. And if we continue abusing our clock
for weeks or months, then all these
chronic diseases can happen. So it’s very important, then,
to know how are these clocks organized so that we can nurture them much better. So as you can imagine, just like in our brain we have a clock
that makes us go to sleep and wake up every day, the same brain clock sends
chemical signals to the rest of the body. But what is really surprising
is that almost every organ in our body, and even every single cell in our body
has its own clock. What does that mean? It means that just like your brain clock
makes us more efficient at solving complex problems
in the middle of the day, and also the brain
needs to sleep at night, every organ has its own
peak performance time at certain times of the day. And every organ needs to sleep,
or rest and rejuvenate, at another time. So all these clocks work together
to give us daily rhythms in sleep, metabolism, mood
and even gut microbiome. But how are these clocks
connected to the outside world? In fact, every morning as we wake up
and open our eyes, bright light goes through our eyes
and resets or synchronizes this clock, so that when daylight
savings time changes, or when we move from
one time zone to another time zone, light synchronizes all of our clocks
to the new season or the new time zone. But the property of light
that resets our clock is very different. Almost 15 years ago, we discovered
a new blue-light-sensing protein called melanopsin. It’s present only in 5,000 squiggly
neurons in our eye. And these light-sensing neurons are literally hard wired
to our brain clock, to the master circadian clock. But they have a very interesting property. They’re less sensitive to light,
and especially to orange colored light. So that means, in the evening, as we move around and find our way
under candle light or dim orange light, the melanopsin is not activated. It sends a signal to the brain
as if it’s dark outside so that the brain clock
makes a lot of melatonin and we get a good night’s sleep. And in the daytime as we wake up, go outside
for at least an hour or so. The daylight is very rich in blue light. It fully activates melanopsin. That synchronizes
the brain clock nicely with the day. It reduces sleepiness and depression,
and increases alertness. But the problem is, we spend
more than 90 percent of our time indoors. And at nighttime, bright screens
and bright light activates melanopsin; it sends a confusing signal to the brain,
and the brain thinks it’s not night yet, so it produces less melatonin,
and we sleep poorly. The next day when we wake up, as we spend most of our time indoors, this indoor light
is not rich in blue light, so it again sends another
confusing signal to the brain, and the brain thinks it’s not day yet. So all the chemicals
that should boost our mood are actually not produced enough. So we kind of go back and forth
between insomnia and fogginess, and if it continues for weeks or months,
then a lot of diseases can happen. And what is interesting is, this is particularly
important for children because their brain is still developing. And when children go through
early childhood circadian disruption, they are more prone
to diseases like ADHD and autism. So this new simple idea, that we need
more bright blue light during the daytime and less light, or darkness, at nighttime, is starting a new lighting revolution. And you are just getting a glimpse
of this new light revolution when your smart screen and computer screen
dim down and turn orange at nighttime. But there is more to it. Just think about it: Circadian lighting
at daycare and schools will promote healthy brain development
and promote learning. Circadian lighting at home,
factories, offices, will promote alertness
and improve productivity. Circadian lighting at hospitals
or retirement homes will promote health
and accelerate healing. And in fact, right now,
there is new circadian lighting in our International Space Station
to promote productivity of our astronauts and make them have better nights’ sleep. So light is not the only factor
that affects our clock. In fact, just like light
in the middle of the night disturbs the brain clock and breaks
the chemical balance in our brain, food at the wrong time
can disturb the peripheral clock and break the metabolic
balance in our body, and that will push us towards disease. Now, let’s figure out how. So in the morning,
our stomach is actually ready with the right amount of hormones
and digestive enzymes, and even good gut microbiome
to digest food. So after we eat our first breakfast, a body absorbs enough carbohydrates
and uses it to fuel our body. At the same time, it saves
a little bit of nutrient as fat. As we continue at lunch and dinner,
the same process continues. And after the last dinner, last bite,
a body slowly goes low on carb. At the same time, the circadian clock
cranks up morning fat. And after a few hours, the clock turns into a reset
and repair rejuvenation mode. That means that it turns on enzymes that will break down
cholesterol and toxins. It also turns on mechanisms
to repair the DNA that we have damaged during the daytime. And a lot of cells that are damaged
on our stomach lining or our skin lining are also replaced with healthy new cells so that allergy-causing chemicals
or bacteria cannot get into our body. So after 12 to 16 hours of fasting,
when we eat our next breakfast, the cycle of nurture,
rejuvenation continues. But imagine if we delay
that last bite late into the night. So in this case, this daily rhythm
in metabolism becomes shallow. There is not enough time to burn fat, and there is not enough time to break down the toxins,
cholesterol, etc. So, you can imagine that somebody
who eats within ten hours might have a much better circadian rhythm, whereas somebody who eats
within 15 hours may not. To test this idea,
we went back to the old lab and brought two identical groups of mice born to the same parents,
raised in the same room, same age. And one group of mice
got the standard Western diet to eat whenever they wanted. And then the second group was trained to eat the same number of calories
from the same food, but they had to eat everything within eight to 12 hours at nighttime
when they’re supposed to eat. And we measured the food
and weighed the mice carefully every week for almost 18 weeks. At the end of 18 weeks, the first group of mice,
who ate randomly, were obese, where at the same time,
they had a host of different diseases – they were really morbidly sick – where the second group
that ate within eight to 12 hours were completely healthy. But what is more surprising is this: If we take those morbidly sick mice and give them the same diet,
same number of calories, and they have to eat
only within eight to ten hours, they become healthy. This was a really earth-shattering,
eureka moment for us, because for the first time
in the history of nutrition science, we found that when we eat is as important
as what or how much we eat. Well then, how do we
translate [that] to humans? The first thing we wanted to know is,
when do people eat? To do that, we started a new study – and people usually sign up for the study
at mycircadianclock.org – and then, since people
love to take pictures, we asked them to take pictures of
every single thing that they eat or drink, and we’d do the rest. So when the pictures come to our server,
we add them on a timeline so that it’s easy for us
to figure out when they eat. And they continue taking pictures
for almost two to three weeks. So that we can take a nice snapshot
of their food life during the weekdays and weekends. And you can see,
for this particular person, he or she eats very randomly
throughout the day. And if you look at the weekday
and weekend pattern, those are also very random. And if you combine
the weekday and weekend, there is another interesting
thing that comes up. It appears as if the person
is on the East coast during the weekday and comes to the West coast
on the weekend, which is also very bad
for our circadian clock. Now, if we combine all of this data and plot it as if
we are looking at a clock, then you can see that this person
was eating almost around the clock. He’s not an outlier, actually. If we look at the first
150 people who had signed up, nearly 50 percent of adults
who actually have regular 8 to 5 jobs, eat for 15 hours or longer. So that means if they have their first bite
at 7:00 in the morning, the last bite or last sip of wine
happens at 9:00 or later. What is interesting is,
if we feed mice even a healthy diet, and they eat for 15 hours or longer, then slowly they become overweight
and they get all these diseases. So that’s why we wanted to ask
a very simple question. We brought back people
who were eating for 15 hours and were a little overweight, and asked them to eat whatever they want
within ten hours of their own choosing, and we wanted to see what happens to them. So within three to four months, these people actually boosted up
their circadian rhythm and they lost the excessive
body weight that they had. And over the last one year, we’ve had thousands of people
from all over the world who are signing up
either through our study or doing this by themselves. They try to eat all of their food
somewhere between 8, 10 or 11 hours. And when they do that, after a few weeks, they’re truly amazed
by the untapped potential of the healing power of circadian rhythm. Almost all of them
lose a little bit of weight, but as they continue,
they actually feel much better, more energetic throughout the day. They sleep much better at night, and their mood is much better;
they feel very sharp. And slowly, over months, they suffer less from different diseases
of the gut, heart, immune system, diabetes and even
some of the mental diseases. So we’re truly excited about this study, but at the same time,
we learned another very important insight, and let me share that with you. That is, circadian clock tunes the potency
of almost every drug that we take for almost every disease. So that means,
at certain times of the day, the drug is more potent and can cure you, but at the wrong time of the day
it can have a more severe adverse effect, as if it’s a poison. So this is really important. And the effect is
not even [only] to drugs, at what time of the day
we take our flu shots, at what time we schedule
our surgery for liver or heart, does matter. Even cancer patients who are going through chemotherapy
or radiation therapy, it really matters whether
they schedule the chemo or radiation in the morning or late in the afternoon. So this new knowledge
about circadian rhythm is poised to start a new revolution
in healthcare and healthy habits. Because the current idea
of taking care of your health by counting calories and counting steps
is just prehistoric. And the same software and tools that our tech companies are using
to make us watch more arts, sleep less and eat around the clock
can be used for something better. We can have devices and sensors that can create a nice circadian
lighting environment around us. Sensors can go on us to monitor
our own circadian rhythm every day and how it interacts
with the real outside world. Devices can prompt us
what to eat and when to eat to boost our circadian rhythm. And even there will be smart pills
and programmed drug pumps that can deliver the right medicine,
at the right dose, at the right time, even in the middle of our sleep, so that we can get cured much faster. So I truly believe that circadian rhythm
has untapped potential to prevent, manage and cure many of the chronic diseases
that affect billions of people. Thank you. (Applause) (Cheers) Thank you.

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